Rebar tying machine

ABSTRACT

A rebar tying machine disclosed herein may include a reel having a wire, a wheel holding the reel and rotatable integrally with the reel, a wheel holder rotatably holding the wheel, and an elastic body interposed between the wheel and the wheel holder. Another rebar tying machine disclosed herein may include a reel having a wire, a wheel holding the reel and rotatable integrally with the reel, and a wheel holder rotatably holding the wheel. The wheel may be movable relative to the wheel holder.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2018-148918, filed on Aug. 7, 2018, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The technique disclosed herein relates to a rebar tying machine.

BACKGROUND

Japanese Patent Application Publication No. 2018-111960 describes a rebar tying machine. This rebar tying machine is provided with a reel having a wire, a wheel holding the reel and rotatable integrally with the reel, and a wheel holder rotatably holding the wheel.

SUMMARY

In the technique of Japanese Patent Application Publication No. 2018-111960, the reel and the wheel engage with each other due to the reel being pressed against the wheel, by which the reel and the wheel rotate integrally. In such a configuration, when the reel is excessively pressed against the wheel due to some reason, a resistance in rotating the reel and the wheel increases. In such a state, excessive load may be applied to an actuator which draws out the wire from the reel. The disclosure herein provides a technique for smoothly rotating a reel in a rebar tying machine in which the reel and a wheel rotate integrally. Further, the disclosure herein provides a technique for suppressing excessive load application to an actuator which draws out a wire from the reel.

A rebar tying machine disclosed herein may comprise a reel having a wire, a wheel holding the reel and rotatable integrally with the reel, a wheel holder rotatably holding the wheel, and an elastic body interposed between the wheel and the wheel holder.

According to the above configuration, even when the reel is excessively pressed against the wheel due to some reason, the elastic body suppresses excessive pressing force from being applied to the reel and the wheel. Due to this, a resistance in rotating the reel and the wheel can be suppressed from increasing. Further, an excessive load application to an actuator which draws out the wire from the reel can be suppressed.

Another rebar tying machine disclosed herein may comprise a reel having a wire, a wheel holding the reel and rotatable integrally with the reel, and a wheel holder rotatably holding the wheel. The wheel may be movable relative to the wheel holder.

According to the above configuration, even when the reel is excessively pressed against the wheel due to some reason, an excessive pressing force application to the reel and the wheel is suppressed by the wheel moving relative to the wheel holder. A resistance in rotating the reel and the wheel can be suppressed from increasing. Further, an excessive load application to the actuator which draws out the wire from the reel can be suppressed.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view seeing a rebar tying machine 2 of an embodiment from an upper left rear side.

FIG. 2 is a perspective view seeing the rebar tying machine 2 of the embodiment from an upper right rear side.

FIG. 3 is a perspective view seeing an internal structure of a tying machine body 4 of the rebar tying machine 2 of the embodiment from the upper right rear side.

FIG. 4 is a perspective view seeing the internal structure of the tying machine body 4 of the rebar tying machine 2 of the embodiment from an upper left front side.

FIG. 5 is a perspective view seeing a reel accommodating chamber 20 of the rebar tying machine 2 of the embodiment from the upper left rear side.

FIG. 6 is a cross-sectional view of an accommodation mechanism 36 of the rebar tying machine 2 of the embodiment.

FIG. 7 is a perspective view seeing a wire reel WR, a turntable 60, and a magnetic sensor 66 of the rebar tying machine 2 of the embodiment from the upper right rear side.

FIG. 8 is a perspective view seeing the wire reel WR of the rebar tying machine 2 of the embodiment from the upper right rear side.

FIG. 9 is a perspective view seeing the turntable 60 of the rebar tying machine 2 of the embodiment from the upper left rear side.

FIG. 10 is a cross-sectional view of the wire reel WR and the turntable 60 of the rebar tying machine 2 of the embodiment, in a state where engagement protrusions 60 c of the turntable 60 are riding on partition walls WRd of the wire reel WR.

FIG. 11 is a cross-sectional view of the wire reel WR and the turntable 60 of the rebar tying machine 2 of the embodiment, in a state where the engagement protrusions 60 c of the turntable 60 are in openings WRe of the wire reel WR.

FIG. 12 is a cross-sectional view of a wire reel WR and a turntable 60 of a rebar tying machine 102 of a comparative example, in a state where engagement protrusions 60 c of the turntable 60 are riding on partition walls WRd of the wire reel WR.

FIG. 13 is a perspective view seeing a wire reel WR, a turntable 60, and an optical sensor 90 of a rebar tying machine 2 of a variant from the upper right rear side.

DETAILED DESCRIPTION

Representative, non-limiting examples of the present disclosure will now be described in further detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing aspects of the present teachings and is not intended to limit the scope of the present disclosure. Furthermore, each of the additional features and teachings disclosed below may be utilized separately or in conjunction with other features and teachings to provide improved rebar tying machines, as well as methods for using and manufacturing the same.

Moreover, combinations of features and steps disclosed in the following detailed description may not be necessary to practice the present disclosure in the broadest sense, and are instead taught merely to particularly describe representative examples of the present disclosure. Furthermore, various features of the above-described and below-described representative examples, as well as the various independent and dependent claims, may be combined in ways that are not specifically and explicitly enumerated in order to provide additional useful embodiments of the present teachings.

All features disclosed in the description and/or the claims are intended to be disclosed separately and independently from each other for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter, independent of the compositions of the features in the embodiments and/or the claims. In addition, all value ranges or indications of groups of entities are intended to disclose every possible intermediate value or intermediate entity for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter.

In one or more embodiments, a rebar tying machine may comprise a reel having a wire, a wheel holding the reel and rotatable integrally with the reel, a wheel holder rotatably holding the wheel, and an elastic body interposed between the wheel and the wheel holder.

According to the above configuration, even when the reel is excessively pressed against the wheel due to some reason, the elastic body suppresses excessive pressing force from being applied to the reel and the wheel. Due to this, a resistance in rotating the reel and the wheel can be suppressed from increasing. Further, an excessive load application to an actuator which draws out the wire from the reel can be suppressed.

In one or more embodiments, the reel may be provided with an opening partitioned by a partition wall. The wheel may include an engagement protrusion which is configured to enter the opening and abut the partition wall in a direction in which the reel rotates.

In the above configuration in which the partition wall of the reel and the engagement protrusion of the wheel abut each other in the direction in which the reel rotates, the reel and the wheel can be ensured to rotate integrally. However, in such a configuration, there may be an incident where the engagement protrusion rides onto the partition wall, instead of entering the opening, when the reel is attached to the wheel. If the engagement protrusion rides on the partition wall, the reel is excessively pressed against the wheel as compared to a case in which the engagement protrusion enters the opening. According to the above configuration, since the elastic body is interposed between the wheel and the wheel holder, the elastic body suppresses the excessive pressing force from being applied to the reel and the wheel even when the engagement protrusion rides on the partition wall. Due to this, the resistance in rotating the reel and the wheel can be suppressed from increasing. Further, the excessive load application to the actuator which draws out the wire from the reel can be suppressed.

In one or more embodiments, the elastic body may be a compression spring.

According to the above configuration, the excessive pressing force application to the reel and the wheel can be efficiently suppressed in the case where the reel is excessively pressed against the wheel.

In one or more embodiments, the rebar tying machine may further comprise a pressing mechanism configured to press the reel against the wheel.

According to the above configuration, even when the reel is excessively pressed against the wheel by the pressing mechanism, the elastic body interposed between the wheel and the wheel holder suppresses the excessive pressing force from being applied to the reel and the wheel. Due to this, the resistance in rotating the reel and the wheel can be suppressed from increasing. Further, the excessive load application to the actuator which draws out the wire from the reel can be suppressed.

In one or more embodiments, the rebar tying machine may further comprise a rotation detecting mechanism configured to detect rotation of the wheel relative to the wheel holder.

In a case of detecting rotation of the reel by using the rotation detecting mechanism as aforementioned, the reel and the wheel needs to be integrally rotated for sure. However, if a configuration in which the reel is firmly pressed against the wheel to ensure the integral rotation of the reel and the wheel is employed, there is a risk that the reel may be excessively pressed against the wheel. According to the above configuration, even when the reel is excessively pressed against the wheel, the elastic body interposed between the wheel and the wheel holder suppresses the excessive pressing force from being applied to the reel and the wheel. Due to this, the resistance in rotating the reel and the wheel can be suppressed from increasing. Further, the excessive load application to the actuator which draws out the wire from the reel can be suppressed.

In one or more embodiments, a rebar tying machine may comprise a reel having a wire, a wheel holding the reel and rotatable integrally with the reel, and a wheel holder rotatably holding the wheel. The wheel may be movable relative to the wheel holder.

According to the above configuration, even when the reel is excessively pressed against the wheel due to some reason, an excessive pressing force application to the reel and the wheel is suppressed by the wheel moving relative to the wheel holder. Due to this, a resistance in rotating the reel and the wheel can be suppressed from increasing. Further, an excessive load application to an actuator which draws out the wire from the reel can be suppressed.

In one or more embodiments, relative to the wheel holder, the wheel may be movable in a direction along a rotation axis of the reel and may be immovable in a direction perpendicular to the rotation axis of the reel.

If a rotation axis of the wheel is displaced from the rotation axis of the reel when the wheel moves relative to the wheel holder, the resistance in integrally rotating the reel and the wheel increases and the excessive load is applied to the actuator which draws out the wire from the reel. According to the above configuration, even when the wheel moves relative to the wheel holder, the rotation axis of the wheel is not displaced from the rotation axis of the reel, thus the resistance in integrally rotating the reel and the wheel can be suppressed from increasing. Further, the excessive load application to the actuator which draws out the wire from the reel can be suppressed.

Embodiments

A rebar tying machine 2 of an embodiment will be described with reference to the drawings. The rebar tying machine 2 shown in FIG. 1 is a power tool for tying a plurality of rebars R by a wire W.

As shown in FIGS. 1 and 2, the rebar tying machine 2 includes a tying machine body 4, a grip 6 provided below the tying machine body 4 for a user to hold, and a battery receiver 8 provided below the grip 6. A battery B can be detachably attached to a lower portion of the battery receiver 8. The battery B is a sliding-type battery which can be attached and detached by being slid relative to the battery receiver 8. The battery B is a lithium ion battery which is rechargeable by a charger, which is not shown, for example. When the battery B is attached to the battery receiver 8, power is supplied from the battery B to the rebar tying machine 2.

The rebar tying machine 2 is provided with a housing 12. The housing 12 is provided with a left housing 14, a right housing 16, and a side cover housing 18. As shown in FIG. 1, the left housing 14 integrally configures an outer shape of a left half of the tying machine body 4, an outer shape of a left half of the grip 6, and an outer shape of a left half of the battery receiver 8. As shown in FIG. 2, the right housing 16 integrally configures an outer shape of a right half of the tying machine body 4, an outer shape of a right half of the grip 6, and an outer shape of a right half of the battery receiver 8. The left housing 14 is fixed to the right housing 16 by a plurality of screws. The side cover housing 18 configures a part of the outer shape of the right half of the tying machine body 4. The side cover housing 18 is fixed to the right housing 16 by a plurality of screws.

A reel accommodating chamber 20 configured to accommodate a wire reel WR (see FIG. 3) on which the wire W is wound is provided at a rear portion of the tying machine body 4. An upper portion of the reel accommodating chamber 20 is covered by a reel cover 22. The reel cover 22 is pivotably supported on the tying machine body 4 via circular ring-shaped receivers 22 a, 22 b provided on left and right sides. The reel cover 22 is configured to open and close the reel accommodating chamber 20 by pivoting relative to the tying machine body 4 with a left-right direction as its pivot axis.

An upper front portion of the grip 6 is provided with a trigger 28 configured to be pulled by a user and a trigger lock 30 provided behind the trigger 28 and configured to switch between a state allowing the trigger 28 to be pulled and a state prohibiting the pull.

As shown in FIGS. 3 and 4, the tying machine body 4 is primarily provided with a control board 34, an accommodation mechanism 36, a feed mechanism 38, a brake mechanism 40, a guide mechanism 42, a cutting mechanism 44, and a twisting mechanism 46. The control board 34 is disposed at a lower portion of the tying machine body 4.

The accommodation mechanism 36 is disposed at the rear portion of the tying machine body 4. The accommodation mechanism 36 detachably holds the wire reel WR accommodated in the reel accommodating chamber 20. The wire reel WR is rotatably supported by the accommodation mechanism 36 in the reel accommodating chamber 20.

The feed mechanism 38 is disposed at an upper portion of the tying machine body 4 in a vicinity of a center thereof in a front-rear direction. The feed mechanism 38 is configured to rotate a feed roller 74 by driving a feed motor 72 to draw out the wire W from the wire reel WR in the accommodation mechanism 36, and feed out the wire W to the guide mechanism 42 provided at a front portion of the tying machine body 4. Operation of the feed motor 72 is controlled by the control board 34.

The guide mechanism 42 is disposed at the front portion of the tying machine body 4. The guide mechanism 42 is configured to guide the wire W fed from the feed mechanism 38 around the plurality of rebars R in a loop shape (see FIG. 1).

The brake mechanism 40 is disposed near the center of the tying machine body 4 in the front-rear direction. The brake mechanism 40 is configured to stop rotation of the wire reel WR in accordance with a timing at which the feed mechanism 38 stops feeding out the wire W. The wire reel WR has notches WRa provided therein at a predetermined angular interval, and the brake mechanism 40 stops the rotation of the wire reel WR by bringing a brake member 78 into engagement with one of the notches WRa by actuating a solenoid 76. Operation of the solenoid 76 is controlled by the control board 34.

The cutting mechanism 44 is disposed at the front portion of the tying machine body 4. The cutting mechanism 44 is configured to cut the wire W, while the wire W is wound around the plurality of rebars R, by a cutter (not shown) which rotates in cooperation with the twisting mechanism 46.

The twisting mechanism 46 is disposed from the front portion across to an intermediate portion of the tying machine body 4 in the front-rear direction. The twisting mechanism 46 includes a hook 82 configured to advance, retreat, and rotate according to rotation of a twisting motor 80. The twisting mechanism 46 is configured to hold and twist the wire W wound around the plurality of rebars R via the hook 82 to tie the plurality of rebars R by the wire W. Operation of the twisting motor 80 is controlled by the control board 34.

As shown in FIG. 1, when the user sets the rebar tying machine 2 with respect to the plurality of rebars R and pulls the trigger 28, the rebar tying machine 2 performs a series of operations of winding the wire W around the plurality of rebars R by the feed mechanism 38, the brake mechanism 40 and the guide mechanism 42; cutting the wire W and twisting the wire W wound around the plurality of rebars R by the cutting mechanism 44 and the twisting mechanism 46.

Hereinbelow, the accommodation mechanism 36 will be described in detail. As shown in FIGS. 5 and 6, the accommodation mechanism 36 is provided with a left supporting mechanism 48 provided on a left side of the reel accommodating chamber 20 and a right supporting mechanism 50 provided on a right side of the reel accommodating chamber 20.

As shown in FIG. 6, the left supporting mechanism 48 is provided with a base member 52, a cam member 54, a shaft member 56, and a compression spring 58. The base member 52 is fixed to the left housing 14 by a plurality of screws. The cam member 54 is disposed to penetrate through the base member 52 and is held by the base member 52 so as to be slidable in the left-right direction. The cam member 54 is provided with a cylindrical cover holder 54 a protruding to outside of the reel accommodating chamber 20. The cover holder 54 a holds the receiver 22 a of the reel cover 22. The receiver 22 b of the reel cover 22 is held slidably by a cylindrical cover holder 18 a provided in the side cover housing 18. As shown in FIG. 5, a cam protrusion 54 b is provided on an outer circumferential surface of the cover holder 54 a. Corresponding to the cam protrusion 54 b of the cover holder 54 a, a cam protrusion (not shown) is provided on an inner circumferential surface of the receiver 22 a of the reel cover 22. As shown in FIG. 6, the shaft member 56 is provided with a cylindrical reel holder 56 a protruding toward inside of the reel accommodating chamber 20. The shaft member 56 is fixed to the cam member 54 by a plurality of screws. Due to this, the shaft member 56 can slide integrally with the cam member 54 in the left-right direction relative to the base member 52. Further, the shaft member 56 is biased in the right direction (that is, toward the inside of the reel accommodating chamber 20) by the compression spring 58 held by the base member 52. In a normal state, the cam member 54 and the shaft member 56 are located to the right relative to the base member 52 (that is, to the inside of the reel accommodating chamber 20) by biasing force of the compression spring 58. In this state, the reel holder 56 a is in a shaft receiving groove WRb of the wire reel WR and the cam protrusion 54 b of the cam member 54 is pressing the cam protrusion of the receiver 22 a in a direction closing the reel cover 22, by which the reel cover 22 is closed. In this state, the reel holder 56 a slidably abuts the shaft receiving groove WRb, thus the wire reel WR is held rotatably relative to the reel holder 56 a. In this state, the wire reel WR is pressed to the right (that is, toward the inside of the reel accommodating chamber 20) by the reel holder 56 a. Then, when the user opens the reel cover 22 against the biasing force of the compression spring 58, the cam protrusion of the receiver 22 a of the reel cover 22 presses the cam protrusion 54 b of the cover holder 54 a to the left (that is, toward the outside of the reel accommodating chamber 20) as the reel cover 22 pivots. Due to this, the cam member 54 and the shaft member 56 move to the left relative to the base member 52 (that is, toward the outside of the reel accommodating chamber 20), and the reel holder 56 a exits from the shaft receiving groove WRb of the wire reel WR. In this state, the user can take out the wire reel WR from the reel accommodating chamber 20 or set the wire reel WR therein.

As shown in FIG. 6, the right supporting mechanism 50 is provided with a turntable 60, an inner bearing 62, an outer bearing 64, a magnetic sensor 66 (see FIG. 3), and a compression spring 68. The turntable 60 is held rotatably by the right housing 16 via the inner bearing 62 and the outer bearing 64. Further, the turntable 60 is slidable in the left-right direction relative to the inner bearing 62 and the outer bearing 64. The turntable 60 is biased to the left (that is, toward the inside of the reel accommodating chamber 20) by the compression spring 68 held by the outer bearing 64. In the normal state, the turntable 60 is located to the left (that is, to the inside of the reel accommodating chamber 20) relative to the right housing 16 by biasing force of the compression spring 68.

The turntable 60 is provided with a cylindrical reel holder 60 a protruding toward the inside of the reel accommodating chamber 20, a disk-shaped rotation detector 60 b disposed along an inner side surface of the reel accommodating chamber 20, and a plurality of substantially triangular and flat plate-shaped engagement protrusions 60 c protruding toward the inside of the reel accommodating chamber 20 (see FIG. 9). As shown in FIG. 8, the wire reel WR includes a shaft receiving groove WRc provided near its rotation axis and a plurality of openings WRe arranged on a radially outer side relative to the shaft receiving groove WRc and partitioned by partition walls WRd in a circumferential direction. The reel holder 60 a is configured to enter the shaft receiving groove WRc of the wire reel WR and slidably abut the shaft receiving groove WRc. Further, the engagement protrusions 60 c are configured to enter the openings WRe of the wire reel WR. When the wire reel WR rotates, static frictional force applied from the shaft receiving groove WRc acts on the reel holder 60 a and the engagement protrusions 60 c abut the partition walls WRd in the circumferential direction, by which the turntable 60 rotates integrally with the wire reel WR. As shown in FIG. 7, a plurality of magnets 60 d is attached to the rotation detector 60 b at a predetermined angular interval. The magnetic sensor 66 is provided with a Hall IC 66 a configured to detect magnetism of the magnets 60 d. As shown in FIG. 3, the magnetic sensor 66 is disposed on an outer side of the right housing 16. The magnetic sensor 66 is electrically connected to the control board 34. When the wire reel WR rotates, the magnets 60 d of the turntable 60 rotate integrally with the wire reel WR and the magnetism detected by the Hall IC 66 a changes. The control board 34 is configured to detect the rotation of the wire reel WR from the change in the magnetism of the magnets 60 detected by het Hal IC 66 a of the magnetic sensor 66.

As shown in FIG. 10, when the wire reel WR is to be set in the accommodation mechanism 36, distal ends of the engagement protrusions 60 c could ride on the partition walls WRd, instead of entering the openings WRe. In such a case, the compression spring 68 is compressed and the turntable 60 moves to the right (that is, toward the outside of the reel accommodating chamber 20). In this state, the reel holder 60 a does not abut the shaft receiving groove WRc, the engagement protrusions 60 c are not in the openings WRe, and the distal ends of the engagement protrusions 60 c abut the partition walls WRd. In this state, although the wire reel WR is pressed toward the turntable 60 of the right supporting mechanism 50 by the shaft member 56 of the left supporting mechanism 48, no large pressing force is applied to the wire reel WR and the turntable 60 since the turntable 60 has moved to the right as the compression spring 68 is compressed. Due to this, the wire reel WR easily rotates relative to the turntable 60 when the feed mechanism 38 draws out the wire W from the wire reel WR by driving the feed motor 72. Thus, when the feed mechanism 38 draws out the wire W from the wire reel WR by driving the feed motor 72, the engagement protrusions 60 c enter the openings WRe and the reel holder 60 a enters the shaft receiving groove WRc as shown in FIG. 11, which brings the wire reel WR to be in its normally held state.

FIG. 12 shows a rebar tying machine 102 of a comparative example in which the compression spring 68 is not provided and the turntable 60 is not slidable in the left-right direction relative to the inner bearing 62 and the outer bearing 64 (that is, the turntable 60 is not movable in the left-right direction relative to the right housing 16). In a case where the distal ends of the engagement protrusions 60 c ride on the partition walls WRd, instead of entering the openings WRe, in the rebar tying machine 102, significantly large pressing force is applied to the wire reel WR and the turntable 60 since the wire reel WR is pressed toward the turntable 60 of the right supporting mechanism 50 by the shaft member 56 of the left supporting mechanism 48. Even when the feed mechanism 38 attempts to draw out the wire W from the wire reel WR by driving the feed motor 72 in this state, the wire reel WR is not able to rotate easily relative to the turntable 60 and the turntable 60 is not able to rotate easily relative to the right housing 16 either, thus a significantly large load is applied to the feed motor 72. Contrary to this, according to the rebar tying machine 2 of the present embodiment shown in FIGS. 10 and 11, the turntable 60 is movable in the left-right direction relative to the right housing 16 and the compression spring 68 is provided between the turntable 60 and the right housing 16, thus the application of significantly large load to the feed motor 72 can be suppressed even when the engagement protrusions 60 c ride on the partition walls WRd.

In the above embodiment, the configuration is exemplified in which the accommodation mechanism 36 is provided with the plurality of magnets 60 d provided on the turntable 60 and the magnetic sensor 66 provided on the right housing 16 for detecting the rotation of the wire reel WR. Different from this, a configuration in which a plurality of magnets is provided directly on the wire reel WR at a predetermined angular interval and the magnets 60 d are not provided on the turntable 60 may be employed. In this case as well, the rotation of the wire reel WR can be detected from a change in magnetism from the magnets on the wire reel WR detected by the magnetic sensor 66. In a case where the rotation of the wire reel WR does not need to be detected, a plurality of magnets may not be provided on the wire reel WR nor on the turntable 60, and the magnetic sensor 66 may not be provided on the right housing 16.

In the above embodiment, the configuration is exemplified in which the accommodation mechanism 36 is provided with the plurality of magnets 60 d provided on the turntable 60 and the magnetic sensor 66 provided on the right housing 16 for detecting the rotation of the wire reel WR. Different from this, as shown in FIG. 13 for example, a configuration may be employed in which the accommodation mechanism 36 is provided with a plurality of reflection plates 60 e provided on the turntable 60 and an optical sensor 90 provided on the right housing 16 for detecting the rotation of the wire reel WR. In the configuration shown in FIG. 13, the optical sensor 90 is provided with a light emitter 90 a configured to emit detection laser toward the wire reel WR and a light receiver 90 b configured to receive laser reflected on the reflection plates 60 e. Each of the light emitter 90 a and the light receiver 90 b of the optical sensor 90 is electrically connected to the control board 34. The plurality of reflection plates 60 e is attached to the rotation detector 60 b of the turntable 60 at a predetermined angular interval. The optical sensor 90 is disposed on the outer side of the right housing 16. The right housing 16 is provided with through holes (not shown) through which the light emitter 90 a and the light receiver 90 b of the optical sensor 90 are exposed to the wire reel WR. According to the configuration shown in FIG. 13, the control board 34 can detect the rotation of the wire reel WR from a change in the light detected by the light receiver 90 b of the optical sensor 90.

In the above embodiment, the configuration in which the wire reel WR is held at the rear portion of the tying machine body 4 is exemplified, however, the wire reel WR may be held at any position other than the above. For example, the wire reel WR and the accommodation mechanism 36 which holds the wire reel WR may be disposed at a position in the lower portion of the tying machine body 4 and in front of the grip 6, such as a position between the guide mechanism 42 and the battery receiver 8, and the feed mechanism 38 and the brake mechanism 40 may be disposed above the accommodation mechanism 36.

In the above embodiment, the configuration in which the rebar tying machine 2 uses one wire reel WR is exemplified, however, a configuration in which the rebar tying machine 2 uses two or more wire reels WR may be employed. For example, the rebar tying machine 2 may be provided with a plurality of accommodation mechanisms 36, a plurality of feed mechanisms 38, and a plurality of brake mechanisms 40, hold a plurality of wire reels WR individually, and feed out wires W to the guide mechanism 42 from the respective wire reels WR.

As above, in one or more embodiments, the rebar tying machine 2 includes the wire reel WR (an example of a reel) having the wire W, the turntable 60 (an example of a wheel) holding the wire reel WR and integrally rotatable with the wire reel WR, the right housing 16 (an example of a wheel holder) rotatably holding the turntable 60, and the compression spring 68 (an example of an elastic body) interposed between the turntable 60 and the right housing 16.

According to the above configuration, even when the wire reel WR is excessively pressed against the turntable 60 due to some reason, the compression spring 68 suppresses excessive pressing force from being applied to the wire reel WR and the turntable 60. Due to this, a resistance in rotating the wire reel WR and the turntable 60 can be suppressed from increasing. Further, an excessive load application to the feed motor 72, which is an actuator that draws out the wire W from the wire reel WR, can be suppressed.

In one or more embodiments, the wire reel WR is provided with the openings WRe partitioned by the partition walls WRd. The turntable 60 includes the engagement protrusions 60 c which are configured to enter the openings WRe and abut the partition walls WRd in a direction in which the wire reel WR rotates.

As above, in the configuration in which the partition walls WRd of the wire reel WR abut the engagement protrusions 60 c of the turntable 60 in the direction in which the wire reel WR rotates, the wire reel WR and the turntable 60 can be ensured to rotate integrally. However, in the configuration as above, the engagement protrusions 60 c could ride on the partition walls WRd, instead of entering the openings WRe, when the wire reel WR is attached to the turntable 60. If the engagement protrusions 60 c ride on the partition walls WRd, the wire reel WR is excessively pressed against the turntable 60 as compared to the case where the engagement protrusions 60 c enter the openings WRe. Since the compression spring 68 is interposed between the turntable 60 and the right housing 16 in the above configuration, the compression spring 68 suppresses excessive pressing force from being applied to the wire reel WR and the turntable 60 even when the engagement protrusions 60 c ride on the partition walls WRd. Due to this, the resistance in rotating the wire reel WR and the turntable 60 can be suppressed from increasing. Further, excessive force application to the feed motor 72, which draws out the wire W from the wire reel WR, can be suppressed.

In one or more embodiments, an elastic body interposed between the turntable 60 and the right housing 16 is the compression spring 68.

According to the above configuration, when the wire reel WR is excessively pressed against the turntable 60, excessive pressing force application to the wire reel WR and the turntable 60 can be effectively suppressed.

In one or more embodiments, the rebar tying machine 2 further includes the left supporting mechanism 48 (an example of a pressing mechanism) configured to press the wire reel WR against the turntable 60.

According to the above configuration, even when the wire reel WR is excessively pressed against the turntable 60 by the left supporting mechanism 48, the compression spring 68 interposed between the turntable 60 and the right housing 16 suppresses excessive pressing force from being applied to the wire reel WR and the turntable 60. Due to this, the resistance in rotating the wire reel WR and the turntable 60 can be suppressed from increasing. Further, excessive load application to the feed motor 72, which draws out the wire W from the wire reel WR, can be suppressed.

In one or more embodiments, the rebar tying machine 2 further includes a rotation detecting mechanism configured to detect rotation of the turntable 60 relative to the right housing 16 (such as the combination of the magnets 60 d and the magnetic sensor 66, or the combination of the reflection plates 60 e and the optical sensor 90).

To detect the rotation of the wire reel WR by using such a rotation detecting mechanism, the wire reel WR and the turntable 60 need to rotate integrally for sure. However, if the wire reel WR is pressed firmly against the turntable 60 to ensure the integral rotation of the wire reel WR and the turntable 60, there is a risk that the wire reel WR might be excessively pressed against the turntable 60. According to the above configuration, even when the wire reel WR is excessively pressed against the turntable 60, the compression spring 68 interposed between the turntable 60 and the right housing 16 suppresses excessive pressing force from being applied to the wire reel WR and the turntable 60. Due to this, the resistance in rotating the wire reel WR and the turntable 60 can be suppressed from increasing. Further, excessive load application to the feed motor 72, which draws out the wire W from the wire reel WR, can be suppressed.

In one or more embodiments, the rebar tying machine 2 includes the wire reel WR (an example of a reel) having the wire W, the turntable 60 (an example of a wheel) holding the wire reel WR and integrally rotatable with the wire reel WR, and the right housing 16 (an example of a wheel holder) rotatably holding the turntable 60. The turntable 60 is movable relative to the right housing 16.

According to the above configuration, even when the wire reel WR is excessively pressed against the turntable 60 due to some reason, the turntable 60 moves relative to the right housing 16, which suppresses excessive pressing force from being applied to the wire reel WR and the turntable 60. A resistance in rotating the wire reel WR and the turntable 60 can be suppressed from increasing. Further, an excessive load application to the feed motor 72, which is an actuator drawing out the wire W from the wire reel WR, can be suppressed.

In one or more embodiments, relative to the right housing 16, the turntable 60 is movable in a direction along the rotation axis of the wire reel WR and is immovable in a direction perpendicular to the rotation axis of the wire reel WR.

If a rotation axis of the turntable 60 is displaced from the rotation axis of the wire reel WR when the turntable 60 moves relative to the right housing 16, the resistance in integrally rotating the wire reel WR and the turntable 60 thereby increases, and the excessive load is applied to the feed motor 72 that draws out the wire W from the wire reel WR. According to the above configuration, even when the turntable 60 moves relative to the right housing 16, the rotation axis of the turntable 60 is not displaced from the rotation axis of the wire reel WR, thus the resistance in integrally rotating the wire reel WR and the turntable 60 can be suppressed from increasing. Further, the excessive load application to the feed motor 72, which draws out the wire W from the wire reel WR, can be suppressed. 

What is claimed is:
 1. A rebar tying machine, comprising: a reel having a wire; a wheel holding the reel and rotatable integrally with the reel; a wheel holder rotatably holding the wheel; and an elastic body interposed between the wheel and the wheel holder.
 2. The rebar tying machine according to claim 1, wherein the reel is provided with an opening partitioned by a partition wall, and the wheel includes an engagement protrusion which is configured to enter the opening and abut the partition wall in a direction in which the reel rotates.
 3. The rebar tying machine according to claim 1, wherein the elastic body is a compression spring.
 4. The rebar tying machine according to claim 1, further comprising a pressing mechanism configured to press the reel against the wheel.
 5. The rebar tying machine according to claim 1, further comprising a rotation detecting mechanism configured to detect rotation of the wheel relative to the wheel holder.
 6. A rebar tying machine, comprising: a reel having a wire; a wheel holding the reel and rotatable integrally with the reel; and a wheel holder rotatably holding the wheel, wherein the wheel is movable relative to the wheel holder.
 7. The rebar tying machine according to claim 6, wherein relative to the wheel holder, the wheel is movable in a direction along a rotation axis of the reel and is immovable in a direction perpendicular to the rotation axis of the reel. 